Evaluation of residual dentin thickness using quantitative light-induced fluorescence technology.

This study aimed to determine whether a correlation exists between residual dentin thickness and quantitative light-induced fluorescence (QLF) values and, if so, to analyze its tendencies. Forty extracted sound human molars were assigned to filled and unfilled groups. The teeth were submerged in a mold with clear acrylic resin. Red utility wax was inserted into the pulp chamber space in the filled group to simulate vital pulp. The specimen was sectioned longitudinally to observe the inside of the pulp space. The samples were cut horizontally from the highest point of the pulp space 2 mm apart. QLF images were then taken of 2 mm, 1 mm, and 0.5 mm samples using the QLF-D Biluminator™ 2 + system. Three operators independently evaluated the QLF images, and the statistical analysis was conducted using one-way analysis of variance, Pearson correlation coefficients, and intraclass correlation coefficients. In the filled group, the mean ΔF values for residual dentin thicknesses of 2 mm, 1 mm, and 0.5 mm were - 3.22, - 7.84, and - 11.52, respectively. In the unfilled group, the mean ΔF values were 0, - 6.90, and - 10.14, respectively. A positive correlation was found between residual dentin thickness and ΔF values (P < 0.05). The intraclass correlation coefficients for observations made by the three operators for the filled and unfilled groups were 0.831 and 0.917, respectively (P < 0.05). In conclusion, residual dentin thickness and ΔF values were significantly correlated and had a highly positive correlation regardless of the QLF device operator.

In vitro response of dental pulp stem cells to dural substitute grafts: Analysis of cytocompatibility and bioactivity.

AIM: The objective of this study was to assess and compare the cytocompatibility of decellularized porcine small intestine submucosal dural graft from Biodesign (BD) and polyester urethane-based Neuro-Patch (NP) dural substitute with the mineral trioxide aggregate (MTA) and the cyanoacrylate-based Histoacryl surgical adhesive. Furthermore, the study evaluated the inflammatory response and osteogenic differentiation of human dental pulp stem cells (hDPSCs) when cultured in direct contact with the dural substitutes in comparison with MTA. METHODOLOGY: The viability of hDPSCs in direct contact with the tested materials was investigated in vitro by a CCK-8 assay. Additionally, the effects of dural substitutes and MTA on the expression of the inflammatory mediator interleukin-6 (IL-6) was investigated via enzyme-linked immunosorbent assay (ELISA), whilst effects on the differentiation were evaluated using alizarin red staining, alkaline phosphatase staining, ELISA and energy-dispersive X-ray elemental mapping. RESULTS: The dural substitutes were cytocompatible and promoted cellular adhesion. The Histoacryl and MTA demonstrated cytotoxicity in fresh preparations but showed a more favourable cellular reaction when set. Investigations of biological activity indicated that dural substitute membranes did not induce an inflammatory response or osteogenic differentiation of hDPSCs. In contrast, MTA induced the expression of IL-6 and alkaline phosphatase activity contributing to enhanced differentiation and mineralization. CONCLUSIONS: The dural substitute membranes showed cytocompatibility, did not provoke an inflammatory response and maintained the stemness of hDPSCs better than MTA. Additionally, the set Histoacryl surgical adhesive demonstrated good biocompatibility. Taken together, these results highlight the potential use of dural substitutes in regenerative endodontic procedures as coronal barriers alternative to MTA to reduce the incidence of intracanal calcifications.

Effect of icariin surface treatment on the resorption of denuded roots after replantation in rat.

AIM: Limiting the incidence of resorption associated with delayed replantation of avulsed teeth is critical for long-term tooth survival. In this study, we assessed whether icariin, a natural product with anti-osteoclastic properties, could reduce root resorption in a rat model of tooth replantation. METHODOLOGY: Cytocompatibility of icariin (10, 20, 40 and 80 µM) was evaluated by CCK-8 proliferation assay in vitro, and an osteoclastogenesis assay was performed to evaluate the effect of icariin on the differentiation of rat bone marrow macrophages and human peripheral blood monocytes into tartrate-resistant acid phosphatase-stained (TRAP+ ) multinucleated giant cells (MNGCs). Differentiation of human periodontal ligament stem cells (hPDLSCs) treated with icariin (10 µM) was also evaluated at 5, 10 and 21 days of osteogenic induction. The first maxillary molars of five-week-old male Sprague-Dawley rats were extracted, denuded of PDL, then treated either with neutralized collagen solution (Carrier control) or icariin in collagen (3 µg/µL) before replantation into their sockets. The animals were euthanized 2 weeks post-surgery for micro-computed tomography (micro-CT) imaging and histological analyses. RESULTS: Icariin was cytocompatible and significantly reduced the differentiation of TRAP+ MNGCs in a dose-dependent manner compared to the control. Moreover, icariin enhanced alkaline phosphatase activity, expression of osteogenic marker genes and proteins, and calcium deposition in hPDLSCs. Micro-CT imaging of the replanted samples demonstrated a significantly higher volume of remaining roots in the icariin-treated group than in the control group. Histological analysis revealed a marked number of resorptive lacunae with TRAP activity in the control group, whereas icariin-treated samples showed signs of functional healing and reduced osteoclastic activity. CONCLUSIONS: Icariin was biocompatible and demonstrated potent anti-osteoclastic and pro-osteogenic properties that reduced resorption and promoted functional healing of denuded roots in a rat maxillary first molar model of replantation. These findings indicate that root surface treatment with icariin may be a clinically relevant and practical method for improving the retention and survival of teeth with compromised PDL after delayed replantation following traumatic avulsion.

Survival and prognostic factors of managing cracked teeth with reversible pulpitis: A 1- to 4-year prospective cohort study.

AIM: This prospective clinical study evaluated the clinical performance of managing cracked teeth with reversible pulpitis through a combination of internal and external splinting and investigated factors that can affect pulp survival after splinting. METHODOLOGY: Thirty-four teeth diagnosed with cracks and reversible pulpitis were enrolled and treated with bidirectional crack splinting: 1) immediate splinting with a stainless-steel band, 2) internal splinting with crack line removal and resin filling and 3) external splinting with a temporary crown followed by final crown placement. If the symptoms remained/recurred, root canal treatment was performed. Patients were followed up at 3, 6 and 12 months, then annually thereafter. Kaplan-Meier survival analysis to calculate the survival of the treated teeth and Cox univariate proportional hazards regression model to investigate prognostic factors were performed. RESULTS: Twenty-nine (97%) teeth were followed up for up to 4 years. The pulp survival rate was 72% after banding and 91% after final crown cementation. No tooth was extracted (100% tooth survival rate). In the univariate Cox proportional hazard test, pain on percussion was the only statistically significant factor (hazard ratio = 11.77). Teeth with pain on percussion at the first visit had a pulp survival rate of 46% during the follow-up period. In comparison, their counterparts without pain had a 94% pulp survival rate. CONCLUSIONS: Bidirectional splinting successfully managed cracked teeth with reversible pulpitis. Pain on percussion (mechanical allodynia) may be an important factor in deciding whether to attempt root canal treatment on symptomatic cracked teeth. A step-by-step approach with bidirectional crack splinting should be encouraged for a cracked tooth with a vital pulp without mechanical allodynia rather than pre-emptive root canal treatment.

Preserving the vitality of teeth adjacent to a large radicular cyst in periapical microsurgery: a case report with 4-year follow-up.

BACKGROUND: Radicular cysts may enlarge considerably, cause extensive bone destruction, and jeopardize the integrity of the associated vital teeth. The different treatment approaches are aimed mainly at eliminating the cystic epithelial membrane while reducing the risk of injury to vital structures. Contrary to other treatment modalities, preapical surgery offers an unequivocal single occasion resolution for the patient. However, it has been associated with higher risk of collateral damages. CASE PRESENTATION: A patient presented with a large radicular cyst originating from a maxillary lateral incisor. The adjacent central and canine teeth initially failed to exhibit responses to sensibility tests but showed signs of vitality. Microsurgical management was aimed at enucleating the cystic membrane while maintaining adjacent teeth vitality. Upon careful and controlled cyst enucleation under the dental operating microscope, the neurovascular bundle of one of the involved teeth was visualized and its integrity was maintained throughout the procedure. RESULTS: The procedure was successful and follow up recalls revealed recovery of normal sensibility of tooth 11 and 13 with complete bone regeneration around their apices. CONCLUSION: Within the limitation of the present case report, we demonstrated that complete excision of large periapical cyst can be performed without sacrificing the vitality of the adjacent teeth, by preserving the integrity of their neurovascular supply through controlled microsurgical enucleation, and by a potential apical vascular repair ensuing unintended injury. Diagnosing the pulp vitality of non-offending teeth whose apices protrude into the cystic lumen is a complex process and can be misleading. Pressure from the growing cyst can inhibit vital teeth responses to neural-based sensibility tests leading to false negative results. Thus, in such cases, the use of blood perfusion-based vitality testing is recommended for correct initial diagnosis.

Effects of fast- and slow-setting calcium silicate-based root-end filling materials on the outcome of endodontic microsurgery: a retrospective study up to 6 years.

OBJECTIVES: The purpose of this retrospective study was to evaluate and compare the effects of fast- and slow-setting calcium silicate-based materials (CSMs) used for root-end filling on the outcome of endodontic microsurgery. MATERIALS AND METHODS: We searched a clinical database for patients who had received endodontic microsurgery between 2001 and 2016. Included cases were divided into two groups according to the type of CSM used for root-end filling: slow-setting CSM (SCSM) and fast-setting CSM (FCSM). The cases in two groups were subjected to 1:1 nearest neighbor propensity score matching for the following variables: age, sex, tooth type, quality of canal filling, lesion type, and postoperative restoration. For each matched case, the outcome was determined as success or failure according to clinical and radiographic evaluations performed at least 1 year after surgery. Multivariate logistic regression analysis was performed to identify prognostic factors and estimate their effects. RESULTS: In total, 304 cases of endodontic microsurgery (179 SCSM and 125 FCSM) were identified, and 1:1 propensity score matching finally included 122 cases from each group. After matching, all covariates were associated with an absolute standardized difference of < 0.1. The overall success rates were 85.2% and 93.4% for the SCSM and FCSM groups, respectively (p = 0.062). Age, tooth type, lesion type, and CSM type were significantly associated with the outcome of endodontic microsurgery (p < 0.05). CONCLUSIONS: Within the limitations, the outcome of endodontic microsurgery using FCSMs was comparable with that of SCSMs. The findings suggest that the type of CSM used for root-end filling, particularly in terms of the initial setting time, could affect the outcome of endodontic microsurgery. CLINICAL RELEVANCE: FCSMs could be considered for use as root-end filling materials in endodontic microsurgery, particularly in complicated clinical situations which require rapid initial setting of the materials.

Dentists' clinical decision-making about teeth with apical periodontitis using a variable-controlled survey model in South Korea.

BACKGROUND: This study, by using a variable-controlled survey model, sought to compare clinical decisions made by dentists with different clinical backgrounds in South Korea regarding teeth with apical periodontitis and to identify factors that influenced decision-making. METHODS: A questionnaire with 36 questions about identical patient information, clinical signs, and symptoms was filled out by participants. Each question referred to a radiograph that had been manipulated using computer software in order to control tooth-related factors. Participants were instructed to record their demographic information and choose the ideal treatment option related to each radiograph. Simple and multivariable logistic regression analyses (p < .05) were used to investigate factors related to the decision to extract the tooth. We divided factors into dentist-related factors (gender, years of experience, and professional registration) and tooth-related factors (tooth position, coronal status, root canal filling status, and size of the periapical radiolucency). Dentists were categorized into three groups, based on professional registration: general dental practitioners (GDPs), endodontists, and other specialists. Simple logistic regression analysis (p < .05) was used to evaluate the tooth-related factors influencing extraction, depending on the dentists' specialty. RESULTS: Participants mostly preferred saving the teeth over extraction. This preference was highest among the endodontists, followed by other specialists and GDPs. Extractions were significantly preferred for molars, teeth with previous root canal fillings, and those with apical lesions greater than 5 mm. CONCLUSIONS: This study suggests that dentists' decision-making regarding teeth with apical periodontitis was associated with their work experience and specialty and influenced by tooth position, root canal filling status, and size of the apical lesion. CLINICAL RELEVANCE: This survey revealed that clinical decision-making related to teeth with apical periodontitis was affected by dentists' specialty and work experience and by tooth-related factors, such as tooth position, root canal filling status, and size of the apical lesion.

Electrically tunable transmission-type beam deflector using liquid crystal with high angular resolution.

Highly efficient transmission-type beam deflectors that have high angular resolution have been widely used for various applications. Continuously tunable beam deflectors have also been needed for many purposes. An indium-tin-oxide (ITO), widely used for transparent electrodes, was placed on the upper and lower glass substrate. The ITO layer on the lower substrate was patterned by the contact mask aligner for relatively wide input and output pad compared to main grating ITO patterns in the active area. These input and output pads on the lower substrate are connected to each driving integrated circuit (IC), which has 360 channels for continuous control. A small pixel pitch of grating patterns of 6 µm (the electrode width is 3 µm with a 3 µm spacing) was developed, and the maximum diffraction angle is calculated and measured at 2.541° with a wavelength of 532 nm. A minimal cell gap of 2.5 µm was applied for the full 2π phase modulation by using a high-birefringence liquid crystal. A driving module for continuous beam steering is also developed and applied to the beam deflector system. A diffraction efficiency of about 50.9% is observed at an angle of diffraction about 2.541°.

Relationship between phosphor properties and chromaticity of phosphor-in-glass.

SiO2-B2O3-ZnO-Li2O glass and four types of phosphors (Y3Al5O12:Ce3+, (Sr,Ba)Si2O2N2:Eu2+, CaAlSiN3:Eu2+, and Lu3Al5O12:Ce3+) with different spectral distributions and thermal properties were prepared to achieve the desired color point based on the relationship between the thermal properties of phosphors and the microstructure of the phosphor-in-glass (PIG). The glass frit was mixed with various contents of phosphors (2.5, 5.0, 7.5, and 10.0 vol%) and then sintered to form a PIG. It was confirmed that the different pore properties of each PIG, caused by the difference in phosphor thermal properties, have a strong influence on the optical properties of the PIG. As the mass change of the phosphor increases, the scattering coefficient of the PIG also increases based on the variations in both pore size and porosity inside the plate. It is apparent that the scattering coefficient is strongly related to the path of converted light and blue light from the light-emitting diode (LED) chip; therefore, the ratio of transmittance to reflectance of each PIG is different, even if each PIG has the same phosphor content. These results indicate that achieving the target LED chromaticity is closely related to the phosphor characteristics and PIG's pore properties.

Pore characteristics for improving luminous efficacy of phosphor-in-glass.

Pores formed during the sintering of a glass/phosphor mixture affect the scattering and path of light within the resulting phosphor-in-glass (PIG) plate. An investigation of the interactions between blue light from an LED chip and pores within a PIG plate is therefore needed to understand the effect of light scattering on the optical properties. To this end, various glass compositions based on SiO2-B2O3-ZnO were prepared so as to better understand the effect of modifiers (i.e., Li2O, Na2O, La2O3, WO3) on the viscosity and pore properties at different sintering temperatures. This study found that PIGs sintered within a given viscosity range exhibit different optical properties depending on their pore size and overall porosity; a higher luminous efficacy observed in the case of intermediate scattering length values was due to an improved interaction between pores and light. This is a significant finding, as ensuring suitable PIG pore characteristics is an important factor in achieving a desired spectrum and high efficacy from white LEDs.

Effect of transmittance on luminescence properties of phosphor-in-glass for LED packaging.

The transmittance of phosphor-in-glass (PIG) color converter material was studied as a factor affecting the luminescence properties of light emitting diode packaging; it is closely related to the residual pores of sintered glass. In this study, the correlation between porosity and optical properties of the glass and PIG plates was investigated. The transmittance, luminescence properties, and porosity were measured by UV-visible spectrometer, integrating sphere and scanning electron microscope, respectively. Transmittance of the sintered glass plate and the luminous efficacy of the PIG plate both increase with decreased porosity, while the light scattering coefficient decreases. Luminescence properties such as emission intensity and color coordinates are also influenced by transmittance of the PIG plate.

In Vivo Experiments with Dental Pulp Stem Cells for Pulp-Dentin Complex Regeneration.

In recent years, many studies have examined the pulp-dentin complex regeneration with DPSCs. While it is important to perform research on cells, scaffolds, and growth factors, it is also critical to develop animal models for preclinical trials. The development of a reproducible animal model of transplantation is essential for obtaining precise and accurate data in vivo. The efficacy of pulp regeneration should be assessed qualitatively and quantitatively using animal models. This review article sought to introduce in vivo experiments that have evaluated the potential of dental pulp stem cells for pulp-dentin complex regeneration. According to a review of various researches about DPSCs, the majority of studies have used subcutaneous mouse and dog teeth for animal models. There is no way to know which animal model will reproduce the clinical environment. If an animal model is developed which is easier to use and is useful in more situations than the currently popular models, it will be a substantial aid to studies examining pulp-dentin complex regeneration.

Influence of Post-Curing in Nitrogen-Saturated Condition on the Degree of Conversion and Color Stability of 3D-Printed Resin Crowns.

Post-curing is the process of applying extra light to complete the polymerization process of 3D printing. The mechanical properties of light-cured three-dimensional (3D) printed resin can be improved by decreasing the oxygen concentrations during post-curing, and nitrogen-saturated post-curing has been applied for this purpose. This study aimed to evaluate and compare the color stability of 3D-printed resin crowns that were post-cured in both normal air and nitrogen-saturated conditions. Crowns were fabricated with a 3D printer and post-cured in normal air (control group; air) or nitrogen-saturated conditions (experimental group; nitrogen). The specimens in each group were subdivided into four subgroups, each exposed to different discoloration agents: distilled water, coffee, wine, and curry. Post-immersion color changes were measured using a digital spectrophotometer and analyzed using repeated-measures ANOVA. Fourier transform infrared (FT-IR) spectroscopy evaluated the degree of conversion of resin over immersion times for both post-curing conditions. Upon comparing the effects of post-curing conditions, a significant difference between the control and experimental groups in terms of immersion time in the wine and curry subgroups was found. FT-IR analysis showed a significant difference in the degree of conversion between the air and nitrogen groups from 10 to 300 s. These findings suggest that nitrogen-saturated post-curing can potentially enhance the conversion rate of 3D-printed resin crowns, thereby improving their color stability.

Resolution enhancement of holographic printer using a hogel overlapping method.

We propose a hogel overlapping method for the holographic printer to enhance the lateral resolution of holographic stereograms. The hogel size is directly related to the lateral resolution of the holographic stereogram. Our analysis by computer simulation shows that there is a limit to decreasing the hogel size while printing holographic stereograms. Instead of reducing the size of hogel, the lateral resolution of holographic stereograms can be enhanced by printing overlapped hogels, which makes it possible to take advantage of multiplexing property of the volume hologram. We built a holographic printer, and recorded two holographic stereograms using the conventional and proposed overlapping methods. The images and movies of the holographic stereograms experimentally captured were compared between the conventional and proposed methods. The experimental results confirm that the proposed hogel overlapping method improves the lateral resolution of holographic stereograms compared to the conventional holographic printing method.

Improved cell disruption of Pichia pastoris utilizing aminopropyl magnesium phyllosilicate (AMP) clay.

An efficient method for Pichia cell disruption that employs an aminopropyl magnesium phyllosilicate (AMP) clay-assisted glass beads mill is presented. AMP clay is functionalized nanocomposite resembling the talc parent structure Si8Mg6O20(OH)4 that has been proven to permeate the bacterial membrane and cause cell lysis. The recombinant capsid protein of cowpea chlorotic mottle virus (CCMV) expressed in Pichia pastoris GS115 was used as demonstration system for their ability of self-assembly into icosahedral virus-like particles (VLPs). The total protein concentration reached 4.24 mg/ml after 4 min treatment by glass beads mill combined with 0.2 % AMP clay, which was 11.2 % higher compared to glass beads mill only and the time was half shortened. The stability of purified CCMV VLPs illustrated AMP clay had no influence on virus assembly process. Considering the tiny amount added and simple approach of AMP clay, it could be a reliable method for yeast cell disruption.

Three-dimensional accuracy of endodontic access preparations using novel nonrestrictive static guides: A laboratory study.

This study compared the accuracy of traditional endodontic access to conservative access cavities prepared with or without novel nonrestrictive endodontic access guides by operators with different levels of clinical experience without visual aids, using a three-dimensional volumetric accuracy analysis method. The accuracy of the preparations was analysed using a novel 3D volumetric analysis by calculating the intersection and volume of the actual cavities to the planned model cavities. The experienced operator significantly outperformed the inexperienced operator in the free hand groups, while accuracy of conservative access cavities prepared using the novel guides were comparable and significantly higher than the other groups (p < 0.05). The results demonstrated clinical experience enhanced endodontic preparations accuracy and that nonrestrictive guides achieve accurate conservative access cavities which are independent of the operator skill level. Additionally, the three-dimensional volumetric analysis is a consistent and objective method to judge the accuracy of guided endodontic techniques.

Biological Function and Potential Applications of Garcinol in Human Dental Pulp Stem Cells.

INTRODUCTION: The regeneration of pulp tissue is crucial for true regenerative endodontic treatment, which requires a reduction in osteogenic differentiation. Garcinol, a histone acetyltransferase inhibitor, is a natural regulator that is known to suppress the osteogenic differentiation of dental pulp stem cells. In this study, the inhibitory effect of garcinol on the osteogenic differentiation of human dental pulp stem cells (hDPSCs) was evaluated using three-dimensional culture under in vitro and in vivo conditions. METHODS: hDPSCs were obtained from caries-free third molars and cultured with 10 µM garcinol for 7 days in an ultra-low attachment plate. The cell stemness and expression of osteogenic differentiation-related genes were analyzed using reverse transcription-polymerase chain reaction and single-cell analysis. A transplantation experiment was performed in mice to investigate whether garcinol-treated hDPSCs showed restrained osteogenic differentiation. RESULTS: hDPSCs cultured in the U-shaped ultra-low attachment plate showed the highest expression of stemness-related genes. Garcinol-treated hDPSCs demonstrated downregulation of osteogenic differentiation, with lower expression of bone sialoprotein, which is related to bone formation, and higher expression of dentin sialophosphoprotein, which is related to dentin formation. However, the garcinol-treated hDPSCs did not show any alterations in their stemness. Consistent results were observed in the transplantation experiment in mice. CONCLUSIONS: Garcinol reduced the osteogenic differentiation of hDPSCs, which can contribute to true regenerative endodontic treatment.

An Endodontic Forecasting Model Based on the Analysis of Preoperative Dental Radiographs: A Pilot Study on an Endodontic Predictive Deep Neural Network.

INTRODUCTION: This study aimed to evaluate the use of deep convolutional neural network (DCNN) algorithms to detect clinical features and predict the three-year outcome of endodontic treatment on preoperative periapical radiographs. METHODS: A database of single-root premolars that received endodontic treatment or retreatment by endodontists with presence of three-year outcome was prepared (n = 598). We constructed a 17-layered DCNN with a self-attention layer (Periapical Radiograph Explanatory System with Self-Attention Network [PRESSAN-17]), and the model was trained, validated, and tested to 1) detect 7 clinical features, that is, full coverage restoration, presence of proximal teeth, coronal defect, root rest, canal visibility, previous root filling, and periapical radiolucency and 2) predict the three-year endodontic prognosis by analyzing preoperative periapical radiographs as an input. During the prognostication test, a conventional DCNN without a self-attention layer (residual neural network [RESNET]-18) was tested for comparison. Accuracy and area under the receiver-operating-characteristic curve were mainly evaluated for performance comparison. Gradient-weighted class activation mapping was used to visualize weighted heatmaps. RESULTS: PRESSAN-17 detected full coverage restoration (area under the receiver-operating-characteristic curve = 0.975), presence of proximal teeth (0.866), coronal defect (0.672), root rest (0.989), previous root filling (0.879), and periapical radiolucency (0.690) significantly, compared to the no-information rate (P < .05). Comparing the mean accuracy of 5-fold validation of 2 models, PRESSAN-17 (67.0%) showed a significant difference to RESNET-18 (63.4%, P < .05). Also, the area under average receiver-operating-characteristic of PRESSAN-17 was 0.638, which was significantly different compared to the no-information rate. Gradient-weighted class activation mapping demonstrated that PRESSAN-17 correctly identified clinical features. CONCLUSIONS: Deep convolutional neural networks can detect several clinical features in periapical radiographs accurately. Based on our findings, well-developed artificial intelligence can support clinical decisions related to endodontic treatments in dentists.

Construction and performance evaluation of mediator-less microbial fuel cell using carbon nanotubes as an anode material.

A microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy using the catalytic reaction of microorganisms. We investigated the performance of mediator-less MFC with carbon nanotubes (CNTs)/graphite felt composite electrodes. The addition of CNTs to a graphite felt electrode increases the specific surface area of the electrode and enhances the charge transfer capability so as to cause considerable improvement of the electrochemical activity for the anode reaction in a MFC. The performance of the MFC using CNTs/graphite felt electrode has been compared against a plain graphite felt electrode based MFC. A CNTs/graphite felt electrode showed as high as 15% increase in the power density (252 mW/m2) compared to graphite felt electrode (214 mW/m2). The CNTs/graphite felt anode therefore offers good prospects for application in MFCs.

Single-Cell RNA Sequencing Analysis of Human Dental Pulp Stem Cell and Human Periodontal Ligament Stem Cell.

INTRODUCTION: Many studies have investigated the transcriptome profiles of dental stem cells for regenerative medicine. However, such studies use bulk RNA and do not consider cell-level heterogeneity. Here, we investigated the characteristics and heterogeneity of human dental pulp stem cells (hDPSCs) and human periodontal ligament stem cells (hPDLSCs) at the single-cell level and examined the differences between them. METHODS: hDPSCs and hPDLSCs were obtained from caries-free premolars (n = 2). Single-cell RNA sequencing of hDPSCs and hPDLSCs was performed using a Single Emulsion Systems (Dolomite Microfluidics, Royston, UK) droplet microfluidic device and the Illumina NextSeq550 system (Illumina, San Diego, CA). Data alignment was performed using STAR v2.4.0, and further analysis was performed using the Seurat, singleR, and clusterProfiler packages in R (R Foundation for Statistical Computing, Vienna, Austria). RESULTS: hDPSCs and hPDLSCs were separated into 3 clusters. hDPSCs mainly exhibited osteogenic and neurogenic cell populations. The main populations of hPDLSCs comprised osteogenic and myofibroblastic populations. hPDLSCs showed high "scores" for osteogenic gene expression, whereas hDPSCs had high neurogenic and endogenic scores. CONCLUSIONS: Single-cell RNA sequencing of hDPSCs and hPDLSCs revealed that the genes were expressed in specific clusters. The results of these analyses can be used as reference databases and valuable resources for further research in dental therapeutics.